With the ever-present dangers of theft and terrorism, security has become a major concern in industries such as cargo and pharmaceutical transportation, retail, money handling and utilities. It has therefore become increasingly important for shippers, retailers, banks and logistics providers to protect their cargo and equipment.
One way in which some form of security can be provided is by using plastic straps, more commonly known as cable ties. Cable ties typically consist of a nylon strap with an integrated gear rack along one end, and a ratchet within a small open case at an opposite end. In use, the strap is fed into the open case such that the gear rack is engaged with the ratchet, which then allows movement of the strap further into the case but not out of the case. The ratchet accordingly prevents the strap from being withdrawn from the case and, when used to seal cargo or other equipment, provides some level of security. However, it is commonly known that a small screwdriver or a needle may be used to pry open the ratchet, which allows a non-destructive removal of the strap. This is undesirable since the seal provided by the cable tie may be removed without much effort and, more importantly, without any visible sign that the seal has been tampered with.
Due to the above shortcomings of plastic straps, reliance has been placed on more complicated and often more expensive designs. Some security seals have relied upon an all-metal construction that requires power tools for removal. The extensive use of metal, however, makes the security seal costly and difficult to handle. Other security seals rely on a detection of electrical conduction or non-conduction to detect tampering, which requires electronics in additional to extensive metal use in their design. There are also known complicated designs for security seals that release ink to indicate tampering.